Abstract: A novel Phillips catalyst for the homopolymerization of ethylene and the copolymerization of ethylene with .alpha.-olefins contains, as a catalytically active component, a chromium catalyst supported on a finely divided aluminum silicate gel, modified with a fluoride and activated in an oxidizing atmosphere at elevated temperatures. The finely divided aluminum silicate gel (carrier gel) used here has an alumina content of from 0.5 to 6% by weight, the alumina being concentrated in the surface region of the carrier gel particles. The novel Phillips catalyst has high productivity and gives high molecular weight ethylene homopolymers and copolymers which have excellent low temperature impact strength and do not tend to swell in the blow molding process on emergence from the extruder die.

Abstract: Propylene-ethylene copolymers are obtained by two-stage polymerization from the gaseous phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system that contains in addition to a titanium-containing solid component also an aluminum compound as co-catalyst, wherein as Ziegler-Natta catalyst system a system is used which, following the reaction of the titanium-containing solid component with the co-catalyst, is deactivated by reaction with carbon dioxide. The copolymers are used for producing fibers, films and moldings.

Abstract: A novel Phillips catalyst for the homopolymerization of ethylene and the copolymerization of ethylene with .alpha.-olefins contains as catalytically active components a specific chromium catalyst on an aluminum phosphate support and cocatalysts of the formula I to IV, ##STR1## where M is lithium, sodium and potassium,M.sup.1 is magnesium and zinc,M.sup.2 is boron and aluminum,R is C.sub.1 -C.sub.10 -alkyl and C.sub.6 -C.sub.20 -aryl,R.sup.1 is R and C.sub.1 -C.sub.10 -alkoxy and C.sub.6 -C.sub.20 -aryloxy,X is chlorine, bromine and iodine,n is 0, 1 and 2The chromium catalyst on an aluminum phosphate support can be obtained by applying chromium compounds to a finely divided aluminum phosphate with a P:A1 molar ratio near to or equal to 1 and a pore volume of >1 cm.sup.3 /g and activating the resulting intermediate at elevated temperatures in an oxidizing atmosphere. The novel Phillips catalyst has an exceptionally long duration of activity and its productivity can be increased further by adding hydrogen.

Abstract: Polymers of propene are prepared using a Ziegler-Natta catalyst system comprising (1) titanium component which is based on a finely divided, shape-imparting silica gel and contains titan- ium, magnesium, chlorine and a benzenecarboxylic acid derivative, (2) an aluminum component and (3) a silane component. The process employs a titanium component (1) which is obtained by a method in which (1.1) first (I) a carrier is prepared from (Ia) a silica gel which has a relatively high moisture content, (Ib) an organomagnesium compound and (Ic) a gaseous chlorinating agent in a manner such that (1.1.1) first (Ia) is reacted with (Ib), (1.1.2) then (Ic) is passed into the mixture obtained from (1.1.1), (1.2) then a solid-phase intermediate is prepared from (I), (II) an alkanol, (III) titanium tetrachloride and (IV) a phthalic acid derivative in a manner such that (1.2.1) first (I) is reacted with (II), (1.2.2) then (III) is introduced into the mixture resulting from (1.2.

Abstract: Ziegler-Natta-type catalyst systems containing, as active constituents,a) a titanium-containing solid component which also contains magnesium, halogen and a carboxylic acid ester, and, as cocatalyst,b) an aluminum compound,wherein the carboxylic acid ester in the solid component is a diester of a carboxylic acid of the formula Ia or Ib ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical or different and are hydrogen, C.sub.1 - to C.sub.15 -alkyl, C.sub.7 - to C.sub.15 -alkylaryl, or 5- to 7-membered cycloalkyl, which may itself carry C.sub.1 - to C.sub.10 -alkyl groups, are particularly suitable for the preparation of polypropylene and copolymers of propylene containing minor amounts of other .alpha.,.beta.-unsaturated olefinic compounds having from 2 to 12 carbon atoms.

Abstract: Ziegler-Natta-type catalyst systems contain as active constituentsa) atitanium-containing solid component which contains titanium, magnesium, halogen and a norbornadienedicarboxylate of the formula I ##STR1## as electron donor, where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.8 -alkyl or 5- to 7-membered cycloalkyl which in turn can carry C.sub.1 -C.sub.10 -alkyl groups,b) an aluminum component andc) another electron donor component,and are particularly suitable for preparing polypropylene and copolymers of propylene with minor amounts of other .alpha.-olefins with 2 to 8 carbon atoms.